As various electronic apparatuses supporting society's infrastructures are made more functional, it is necessary that the speed and density of the electronic apparatuses are further increased. As a result, the electronic apparatuses need to be designed so that the electromagnetic noise emitted from the electronic apparatuses does not cause electromagnetic interference in the inside thereof or with other apparatuses. Further, when an electromagnetic interference problem occurs, the survey needs to be quickly performed on site. Therefore, an apparatus, which detects and visualizes the source of the electromagnetic noise in real time, is required.
As a technique which detects and visualizes electromagnetic waves, there are Patent Literature 1 (JP-A-2013-130466) and Patent Literature 2 (WO2010/013408). In Patent Literature 1, it is described that “an electromagnetic wave visualization apparatus includes: an emission direction separation section which changes the emission direction of electromagnetic waves according to the incident direction of the electromagnetic waves; a plurality of sensors, each of which senses the energy of electromagnetic waves emitted from the emission direction separation section and outputs a detection signal of the intensity corresponding to the amount of the sensed energy; a processing section which can receive the detection signal of each of the plurality of sensors, and which, when receiving the detection signal from the sensor, outputs a display signal including information on the arrival direction of electromagnetic waves, which information is obtained with reference to a table and on the basis of the position information of the sensor, from which the detection signal is transmitted; and a display section which can display each of the electromagnetic wave direction of arrivals, and which, when receiving the display signal, displays the electromagnetic wave direction of arrival on the basis of the electromagnetic wave direction of arrival information that is obtained from the sensor position information included in the display signal”.
Further, in Patent Literature 2, there are described “a radio wave intensity measuring apparatus, and a radio wave intensity measurement system, each of which can measure the intensity of radio waves in a short time by including: a radio wave absorbing section provided with a plane having a plurality of cells that absorb radio waves incident on the plane; and a measurement section that measures the intensity of radio waves at the plurality of cells”.